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#ifndef RBIMPL_INTERN_HASH_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_INTERN_HASH_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Public APIs related to ::rb_cHash.
*/
#include "ruby/internal/attr/nonnull.h"
#include "ruby/internal/dllexport.h"
#include "ruby/internal/value.h"
#include "ruby/st.h"
RBIMPL_SYMBOL_EXPORT_BEGIN()
/* hash.c */
RBIMPL_ATTR_NONNULL(())
/**
* Identical to rb_st_foreach(), except it raises exceptions when the callback
* function tampers the table during iterating over it.
*
* @param[in] st Table to iterate over.
* @param[in] func Callback function to apply.
* @param[in] arg Passed as-is to `func`.
* @exception rb_eRuntimeError `st` was tampered during iterating.
*
* @internal
*
* This is declared here because exceptions are Ruby level concept.
*
* This is in fact a very thin wrapper of rb_st_foreach_check().
*/
void rb_st_foreach_safe(struct st_table *st, st_foreach_callback_func *func, st_data_t arg);
/** @alias{rb_st_foreach_safe} */
#define st_foreach_safe rb_st_foreach_safe
/**
* Try converting an object to its hash representation using its `to_hash`
* method, if any. If there is no such thing, returns ::RUBY_Qnil.
*
* @param[in] obj Arbitrary ruby object to convert.
* @exception rb_eTypeError `obj.to_hash` returned something non-Hash.
* @retval RUBY_Qnil No conversion from `obj` to hash defined.
* @retval otherwise Converted hash representation of `obj`.
* @see rb_io_check_io
* @see rb_check_array_type
* @see rb_check_string_type
*
* @internal
*
* There is no rb_hash_to_hash() that analogous to rb_str_to_str().
* Intentional or ...?
*/
VALUE rb_check_hash_type(VALUE obj);
RBIMPL_ATTR_NONNULL(())
/**
* Iterates over a hash. This basically does the same thing as
* rb_st_foreach(). But because the passed hash is a Ruby object, its keys and
* values are both Ruby objects.
*
* @param[in] hash An instance of ::rb_cHash to iterate over.
* @param[in] func Callback function to yield.
* @param[in] arg Passed as-is to `func`.
* @exception rb_eRuntimeError `hash` was tampered during iterating.
*/
void rb_hash_foreach(VALUE hash, int (*func)(VALUE key, VALUE val, VALUE arg), VALUE arg);
/**
* Calculates a message authentication code of the passed object. The return
* value is a very small integer used as an index of a key of a table. In
* order to calculate the value this function calls `#hash` method of the
* passed object. Ruby provides you a default implementation. But if you
* implement your class in C, that default implementation cannot know the
* underlying data structure. You must implement your own `#hash` method then,
* which must return an integer of uniform distribution in a sufficiently
* instant manner.
*
* @param[in] obj Arbitrary Ruby object.
* @exception rb_eTypeError `obj.hash` returned something non-Integer.
* @return A small integer.
* @note `#hash` can return very big integers, but they get truncated.
*/
VALUE rb_hash(VALUE obj);
/**
* Creates a new, empty hash object.
*
* @return An allocated new instance of ::rb_cHash.
*/
VALUE rb_hash_new(void);
/**
* Identical to rb_hash_new(), except it additionally specifies how many keys
* it is expected to contain. This way you can create a hash that is large enough
* for your need. For large hashes it means it won't need to be reallocated and
* rehashed as much, improving performance.
*
* @param[in] capa Designed capacity of the hash.
* @return An empty Hash, whose capacity is `capa`.
*/
VALUE rb_hash_new_capa(long capa);
/**
* Duplicates a hash.
*
* @param[in] hash An instance of ::rb_cHash.
* @return An allocated new instance of ::rb_cHash, whose contents are
* a verbatim copy of from `hash`.
*/
VALUE rb_hash_dup(VALUE hash);
/** @alias{rb_obj_freeze} */
VALUE rb_hash_freeze(VALUE obj);
/**
* Queries the given key in the given hash table. If there is the key in the
* hash, returns the value associated with the key. Otherwise it returns the
* "default" value (defined per hash table).
*
* @param[in] hash Hash table to look into.
* @param[in] key Hash key to look for.
* @return Either the value associated with the key, or the default one if
* absent.
*/
VALUE rb_hash_aref(VALUE hash, VALUE key);
/**
* Identical to rb_hash_aref(), except it always returns ::RUBY_Qnil for
* misshits.
*
* @param[in] hash Hash table to look into.
* @param[in] key Hash key to look for.
* @return Either the value associated with the key, or ::RUBY_Qnil if
* absent.
* @note A hash can store ::RUBY_Qnil as an ordinary value. You cannot
* distinguish whether the key is missing, or just its associated
* value happens to be ::RUBY_Qnil, as far as you use this API.
*/
VALUE rb_hash_lookup(VALUE hash, VALUE key);
/**
* Identical to rb_hash_lookup(), except you can specify what to return on
* misshits. This is much like 2-arguments version of `Hash#fetch`.
*
* ```CXX
* VALUE hash;
* VALUE key;
* VALUE tmp = rb_obj_alloc(rb_cObject);
* VALUE val = rb_hash_lookup2(hash, key, tmp);
* if (val == tmp) {
* printf("misshit");
* }
* else {
* printf("hit");
* }
* ```
*
* @param[in] hash Hash table to look into.
* @param[in] key Hash key to look for.
* @param[in] def Default value.
* @retval def `hash` does not have `key`.
* @retval otherwise The value associated with `key`.
*/
VALUE rb_hash_lookup2(VALUE hash, VALUE key, VALUE def);
/**
* Identical to rb_hash_lookup(), except it yields the (implicitly) passed
* block instead of returning ::RUBY_Qnil.
*
* @param[in] hash Hash table to look into.
* @param[in] key Hash key to look for.
* @exception rb_eKeyError No block given.
* @return Either the value associated with the key, or what the block
* evaluates to if absent.
*/
VALUE rb_hash_fetch(VALUE hash, VALUE key);
/**
* Inserts or replaces ("upsert"s) the objects into the given hash table. This
* basically associates the given value with the given key. On duplicate key
* this function updates its associated value with the given one. Otherwise it
* inserts the association at the end of the table.
*
* @param[out] hash Target hash table to modify.
* @param[in] key Arbitrary Ruby object.
* @param[in] val A value to be associated with `key`.
* @exception rb_eFrozenError `hash` is frozen.
* @return The passed `val`
* @post `val` is associated with `key` in `hash`.
*/
VALUE rb_hash_aset(VALUE hash, VALUE key, VALUE val);
/**
* Swipes everything out of the passed hash table.
*
* @param[out] hash Target to clear.
* @exception rb_eFrozenError `hash`is frozen.
* @return The passed `hash`
* @post `hash` has no contents.
*/
VALUE rb_hash_clear(VALUE hash);
/**
* Deletes each entry for which the block returns a truthy value. If there is
* no block given, it returns an enumerator that does the thing.
*
* @param[out] hash Target hash to modify.
* @exception rb_eFrozenError `hash` is frozen.
* @retval hash The hash is modified.
* @retval otherwise An instance of ::rb_cEnumerator that does it.
*/
VALUE rb_hash_delete_if(VALUE hash);
/**
* Deletes the passed key from the passed hash table, if any.
*
* @param[out] hash Target hash to modify.
* @param[in] key Key to delete.
* @retval RUBY_Qnil `hash` has no such key as `key`.
* @retval otherwise What was associated with `key`.
* @post `hash` has no such key as `key`.
*/
VALUE rb_hash_delete(VALUE hash, VALUE key);
/**
* Inserts a list of key-value pairs into a hash table at once. It is
* semantically identical to repeatedly calling rb_hash_aset(), but can be
* faster than that.
*
* @param[in] argc Length of `argv`, must be even.
* @param[in] argv A list of key, value, key, value, ...
* @param[out] hash Target hash table to modify.
* @post `hash` has contents from `argv`.
* @note `argv` is allowed to be NULL as long as `argc` is zero.
*
* @internal
*
* What happens for duplicated keys? Well it silently discards older ones to
* accept the newest (rightmost) one. This behaviour also mimics repeated call
* of rb_hash_aset().
*/
void rb_hash_bulk_insert(long argc, const VALUE *argv, VALUE hash);
/**
* Type of callback functions to pass to rb_hash_update_by().
*
* @param[in] newkey A key of the table.
* @param[in] oldkey Value associated with `key` in hash1.
* @param[in] value Value associated with `key` in hash2.
* @return Either one of the passed values to take.
*/
typedef VALUE rb_hash_update_func(VALUE newkey, VALUE oldkey, VALUE value);
/**
* Destructively merges two hash tables into one. It resolves key conflicts by
* calling the passed function and take its return value.
*
* @param[out] hash1 Target hash to be modified.
* @param[in] hash2 A hash to merge into `hash1`.
* @param[in] func Conflict reconciler.
* @exception rb_eFrozenError `hash1` is frozen.
* @exception rb_eRuntimeError `hash2` is updated instead.
* @return The passed `hash1`.
* @post Contents of `hash2` is merged into `hash1`.
* @note You can pass zero to `func`. This means values from `hash2`
* are always taken.
*/
VALUE rb_hash_update_by(VALUE hash1, VALUE hash2, rb_hash_update_func *func);
/* file.c */
/**
* This function is mysterious. What it does is not immediately obvious. Also
* what it does seems platform dependent.
*
* @param[in] path A local path.
* @retval 0 The "check" succeeded.
* @retval otherwise The "check" failed.
*/
int rb_path_check(const char *path);
/* hash.c */
/**
* Destructively removes every environment variables of the running process.
*
* @return The `ENV` object.
* @post The process has no environment variables.
*/
VALUE rb_env_clear(void);
/**
* Identical to #RHASH_SIZE(), except it returns the size in Ruby's integer
* instead of C's.
*
* @param[in] hash A hash object.
* @return The size of the hash.
*/
VALUE rb_hash_size(VALUE hash);
RBIMPL_SYMBOL_EXPORT_END()
#endif /* RBIMPL_INTERN_HASH_H */